U.S. patent application number 13/824441 was filed with the patent office on 2013-10-03 for method for manufacturing an object by solidifying powder using a laser beam with the insertion of a member for absorbing deformations.
This patent application is currently assigned to PHENIX SYSTEMS. The applicant listed for this patent is Patrick Teulet. Invention is credited to Patrick Teulet.
Application Number | 20130256953 13/824441 |
Document ID | / |
Family ID | 46044674 |
Filed Date | 2013-10-03 |
United States Patent
Application |
20130256953 |
Kind Code |
A1 |
Teulet; Patrick |
October 3, 2013 |
METHOD FOR MANUFACTURING AN OBJECT BY SOLIDIFYING POWDER USING A
LASER BEAM WITH THE INSERTION OF A MEMBER FOR ABSORBING
DEFORMATIONS
Abstract
Method for manufacturing an object, includes: a) depositing a
first layer of powder onto a work area constituted by a plate; b)
compacting the first layer; c) solidifying a first area of the
layer compacted in step b) using a laser beam, the area
corresponding to a section of the bottom of the finished object;
and d) repeating steps a) through c) until the object is obtained.
An additional step e) before step c) includes producing, by
solidifying a powder using the laser beam, a member for absorbing
deformations to be arranged between the work area and an area to be
part of an area corresponding to a portion of a bottom of the
finished object. The absorption member produced includes a
deformable substrate including a plurality of blades capable of
connecting a surface of the plate to the first area constituting a
surface of a bottom of the object.
Inventors: |
Teulet; Patrick; (Riom,
FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Teulet; Patrick |
Riom |
|
FR |
|
|
Assignee: |
PHENIX SYSTEMS
Riom
FR
|
Family ID: |
46044674 |
Appl. No.: |
13/824441 |
Filed: |
April 27, 2012 |
PCT Filed: |
April 27, 2012 |
PCT NO: |
PCT/EP12/57825 |
371 Date: |
June 4, 2013 |
Current U.S.
Class: |
264/497 |
Current CPC
Class: |
B22F 3/1055 20130101;
B33Y 10/00 20141201; Y02P 10/295 20151101; B33Y 40/00 20141201;
B29C 64/40 20170801; B22F 2003/1056 20130101; B22F 2999/00
20130101; Y02P 10/25 20151101; B29C 64/153 20170801; B22F 2003/1058
20130101; B22F 2999/00 20130101; B22F 3/16 20130101; B22F 3/02
20130101; B22F 3/1055 20130101 |
Class at
Publication: |
264/497 |
International
Class: |
B29C 67/00 20060101
B29C067/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 29, 2011 |
FR |
1153683 |
Claims
1-5. (canceled)
6. Method for manufacturing an object (0) by solidifying powder (3)
using a laser beam (4) including at least steps consisting of: a)
depositing a first layer (6) of powder (3) onto a work area
constituted by a plate (1), b) compacting said first layer (6), c)
solidifying a first area (7) of the layer compacted in step b)
using a laser beam, said area corresponding to a section of the
bottom wall (9) of the finished object (O), d) repeating steps a)
to c) until the object (O) is obtained, e) before step c),
producing, by solidifying a powder (3) using the laser beam (4), a
member (12) for absorbing deformations arranged between the work
area (1) and an area to be part of an area (7) corresponding to a
section of the bottom wall (9) of the finished object (O) produced
in step c), wherein the absorbing member produced in step e)
comprises a deformable substrate (12) consisting of a plurality of
strips (120) suitable for connecting a surface (2) of the plate (1)
to the first area (7) constituting a surface (9) of the bottom wall
of the object (O).
7. Method according to claim 6, wherein the strips (120) are spaced
at regular intervals.
8. Method according to claim 6, wherein the strips (120), before
any absorption of deformations, are parallel.
9. Method according to claim 6, wherein the powder (3) constituting
the deformable substrate (12) is identical at least to the first
layer (7) of powder (3) constituting the object (O).
10. Method according to claim 6, wherein the powder constituting
the deformable substrate (12) is different at least to the first
layer of powder constituting the object.
Description
[0001] The invention relates to a method for manufacturing an
object by solidifying powder using a laser beam, with the insertion
of a member for absorbing deformations.
[0002] Herein, the term powder should be understood to denote a
powder or a powder mixture. This powder, or this powder mixture,
may be mineral, for example ceramic, or metallic. The term
solidification denotes a method for manufacturing an object by
successively solidifying a plurality of overlaid layers of powder
or powder mixture. These layers are previously spread and compacted
on a plate acting as a work area. Each layer of powder, or powder
mixture, is solidified at areas constituting the walls of the
object, using a laser beam. Such solidification is also referred to
as sintering and this term will be used hereinafter.
[0003] When manufacturing thick-walled and/or large objects, the
appearance of some deformations may be observed. These deformations
occur when the constituent material of the object, i.e. the
solidified powder, has reached a certain temperature after
treatment with the laser beam. The temperature reached in the
layers of sintered powder constituting the walls of the object is
dependent not only on the thermal energy provided by the laser beam
but also on the thermal conductivity coefficient of the solidified
powder. Furthermore, due to the size thereof, the shape thereof
and/or the type of powder, the object has a given linear expansion
coefficient. Insofar as the object is manufactured on a plate made
of a rigid material, this plate also has a specific thermal
conductivity coefficient and expansion coefficient.
[0004] During the production process, the object has a temperature
varying in the course of production, i.e. it increases at each
passage of the laser beam. In parallel with the temperature rise in
the object, a temperature rise in the plate acting as the work
surface is observed.
[0005] The temperature of the sintered object is, in principle,
always greater than that of the plate since the object receives the
energy emitted by the laser beam. If the expansion coefficient of
the plate is greater than or equal to that of the object, a first
type of deformation of the plate is observed. In this case, the
plate has a surface, intended to be in contact with a complementary
surface of the object, which is convex. This deformation of the
plate impacts the object which thus exhibits complementary
deformation, i.e. the object has at least one concave surface
intended to be in contact with the convex face of the plate.
[0006] On the other hand, if the expansion coefficient of the
object is greater than that of the plate, since the temperature of
the object is always greater than that of the plate, another type
of deformation is observed. In this case, at least one surface of
the object, intended to be in contact with the plate, is concave.
In this case, the plate exhibits complementary deformation, i.e.
with at least one convex surface intended to be in contact with the
object.
[0007] If the temperature of the object is less than that reached
by the plate, regardless of the respective expansion coefficients
of the object and the plate, deformation of one surface of the
object intended to be in contact with the plate, which is convex
whereas the complementary surface of the plate is concave, is
observed.
[0008] One of the known solutions for remedying these deformations
is that of using, both for the plate and for manufacturing the
object, materials wherein the thermal conductivity and/or expansion
coefficients are sufficiently similar for the dimensional
variations of the plate and the object to be equivalent. This is
difficult to carry out since not all objects are made from powder
having a similar expansion coefficient to that of the constituent
material of the plate, at least in terms of mechanical
properties.
[0009] Furthermore, the temperatures of the object and the plate
vary during the production process. For this reason, deformations
may occur to varying degrees according to the temperatures.
[0010] EP-A-2 022 622 describes a method for manufacturing an
object held in position in a frame, during the manufacture thereof,
by braces having a complex shape arranged on the periphery of the
object. These braces are not effective in preventing the appearance
of deformations, insofar as the object retains a bottom wall
surface in contact with the plate. Moreover, these braces require
the use of a large volume of powder and a plate having relatively
larger dimensions than those of the finished object, which is not
satisfactory.
[0011] The invention is more specifically intended to remedy these
drawbacks by offering a method which is easy to implement and
mitigating most deformations.
[0012] For this purpose, the invention relates to a method for
manufacturing an object by solidifying powder as defined in claim
1.
[0013] In this way, with a member for absorbing deformations
arranged between the object and the plate, during the manufacture
of the object, any deformations are absorbed, both on the plate and
the object, regardless of the temperatures, thermal conductivity
and/or expansion coefficients of the object and the plate.
[0014] Advantageous, but optional, aspects of this method are
defined in claims 2 to 5.
[0015] The invention will be understood better and further
advantages thereof will emerge more clearly on reading the
description hereinafter of two embodiments of a manufacturing
method by solidifying powder using a laser according to the
invention, given merely as an example and with reference to the
appended figures wherein:
[0016] FIG. 1 is a schematic side view of the production of an
object by means of a method according to the prior art, wherein the
object is represented partially finished,
[0017] FIG. 2 is a schematic side view of a finished object, after
solidification, in position on a plate acting as a work area,
wherein the whole exhibits no deformation,
[0018] FIGS. 3 and 4 illustrate side views of the finished object
and the plate, in the case of both known types of deformation,
wherein the object and plate, without deformation, are illustrated
with phantom lines,
[0019] FIG. 5 is a view of one side of a finished object and the
plate, in FIGS. 3 and 4, a member for absorbing deformations,
produced according to the method according to a first embodiment of
the invention, in the case of absorption of the type of deformation
illustrated in FIG. 3 represented, wherein the deformation is
illustrated with phantom lines,
[0020] FIG. 6 is a view, on a larger scale, of the detail VI in
FIG. 5, and
[0021] FIGS. 7 and 8 are figures equivalent to FIGS. 5 and 6 in the
case of the type of deformation illustrated in FIG. 4.
[0022] In FIG. 1, a plate 1 acts as a work area. The plate 1 has a
plane surface 2 whereon a powder 3 is spread. The term powder in
this instance denotes a powder or powder mixture, regardless of the
nature of the powder(s), i.e. mineral or metallic.
[0023] This powder 3 is solidified using a laser beam 4, i.e.
sintered, to produce the walls of an object O. The plate 1 is
translatably movable along a vertical direction with reference to
FIG. 1. It is movable in a sleeve 5, along the arrow F, so as to be
lowered so that a member for spreading and supplying powder, not
shown and known per se, can provide at the same level, a further
layer 6 of powder 3. This layer 6, represented by a bold solid line
for clear legibility, is spread and compacted before solidifying
using a laser on the previously layer of powder that has already
been sintered. In other words, using this method, layer by layer,
the walls of the object O are produced. The object is represented
schematically in the form of a rectangle, it being understood that
it may a more complex shape. Each layer of solidified powder
represents a section of a wall of the object O.
[0024] On either side of an area 7 of sintered powder 3, an area of
the layer 6 of non-sintered and compacted powder 3 remains. The
area 7 sintered by the laser beam 4 corresponds to a portion of at
least one surface 80, 81, 82, 9 of the object O illustrated in
FIGS. 1 to 5 and 7. Such an object O, which is finished and free
from deformation, is illustrated in position on the plate 1 in FIG.
2. In this case, the surfaces in contact with the plate 1 and the
object O, i.e. with reference to FIG. 2, the top surface 2 of the
plate 1 and the bottom wall surface 9 of a bottom wall of the
object O, are plane and free from deformation. In other words, the
surfaces 2, 9 of the plate 1 and the object O, respectively, are in
contact on the entire respective areas thereof. The object O thus
has an optimal quality.
[0025] If, as shown in FIG. 3, the temperature T0 of the sintered
object O is greater than the temperature T1 of the plate 1, during
the same sintering method, but the expansion coefficient D0 of the
object is greater than the expansion coefficient D1 of the plate 1,
i.e. T0>T1 and D0>D1, the object O expands first and, due to
the dimensions and volume thereof, induces a type of deformation
also affecting the plate 1. It should be noted that, in general,
the temperature T0 of the object O is greater than the temperature
T1 of the plate 1 since the energy emitted by the laser impacts the
object O first and primarily.
[0026] In this case, the surfaces 9, 2 of the object O and the
plate 1 in contact are not plane but are concave for the surface 2
and convex for the surface 9. The concavities 21, 91 of the
surfaces 2, 9 are thus oriented upwards, with reference to FIG.
3.
[0027] If, as illustrated in FIG. 4, the temperature T0 reached by
the object O, once sintered, is greater than the temperature T1
reached by the plate 1, during the same sintering method, and the
expansion coefficient D0 of the object is less than or equal to the
expansion coefficient D1 of the plate 1, i.e. T0>T1 and
D0.ltoreq.D1, a second type of deformation of the plate 1 inducing
similar deformation of the object O is observed.
[0028] In this case, the surface 2, 9 of the plate 1 and the object
O in contact are no longer plane but the surface 2 is convex and
the surface 9 is concave. Such a deformation of the surfaces 2, 9
induces similar deformation of the other surfaces of the plate 1
and the object O. In other words, the assembly consisting of the
plate 1 and object O is bent such that the concavities 20, 90 of
the surfaces 2, 9 are oriented in the same direction, i.e.
downwards, with reference to FIG. 4.
[0029] In other words, in this design, the plate 1 and object O
assembly is bent in the opposite direction with respect to that
represented in FIG. 3.
[0030] It should be noted that, if the expansion coefficients D0
and D1 of the object O and plate 1 are similar, i.e. D0.apprxeq.D1
and the plate 1 is at a temperature T1 less than that T0 of the
object O, i.e. T1<T0, a type of deformation similar to that
illustrated in FIG. 3 is observed. The concavities 21, 91 of the
surfaces 2, 9 are oriented upwards with reference to FIG. 3.
[0031] To prevent, or at least limit, the appearance of these
concave or convex deformations during the method for manufacturing
the object, a member for absorbing deformations 12 inserted between
the surfaces 9, 2 of the object O and the plate 1 is produced
during the manufacturing method. The surface 9 is part of at least
a portion of a bottom wall of the object O. This absorbing member
12 comprises a substrate suitable for absorbing the deformations
due to the effects of the difference between the temperatures T0,
T1 and/or the expansion coefficients D0, D1, regardless of the type
of deformation.
[0032] This deformable substrate 12 is advantageously produced
during the method for sintering the powder 3 i.e. during the method
for manufacturing the object by solidifying the powder using a
laser. In this instance, it is produced before performing a first
solidification, using the laser beam 4, of the first layer 6 of
powder 3 forming a bottom wall of the object O.
[0033] For this, a substrate 12 is formed in a layer 6 of powder,
of the same type as that constituting the object O. Alternatively,
the powder used is different to the powder constituting the object
O.
[0034] Advantageously, as represented in FIGS. 5 to 8, the
substrate is formed of a plurality of flat strips 120, distributed
over a surface area equivalent to that of the base of the object to
be manufactured. Each strip 120 has a minimum length corresponding
to the width of the wall of the object to be manufactured, over a
height of 2 mm to 10 mm for a thickness of 0.1 mm to 0.5 mm. The
maximum length of each strip 120 is approximately 30 mm. To
optimise the absorption of the deformations for widths of the
object O greater than 30 mm, a plurality of strips 120 are arranged
behind each other, at intervals of approximately 0.5 mm, ensuring
that these strips 120 having the same length. For example, for a
width of the object O of 31 mm, two strips 120 are produced,
measuring 15.25 mm in length at 0.5 mm intervals.
[0035] These strips 120 are spaced at regular intervals and
parallel with each other in the absence of deformation. The space E
between two adjacent strips 120 is between 0.1 mm and 1 mm. This
space E is suitable for the geometry of the object O to be
manufactured. Each strip 120 is attached by one end 13 to the plate
1 and by another end 14 to the object O.
[0036] As illustrated in FIGS. 5 and 7, the strips 120 are
identical and occupy the entire available surface area of the
surface 9 of the object O intended to be facing the complementary
surface 2 of the plate 1. In an alternative embodiment not shown,
these strips 120 are only arranged on a portion of these surfaces
2, 9, in this instance at the areas corresponding to the finished
sides of the object.
[0037] In one embodiment not shown, the strips are not identical,
the shape and/or size thereof varying according to the position
occupied.
[0038] The choice made for the density and position of the strips
120 is dependent on the expected deformations and/or dimensions of
the final object.
[0039] The use of strips 120, to produce a substrate 12 makes it
possible to discharge similarly to a heat sink a portion of the
thermal energy supplied by the laser beam 4, by means of the space
E between two adjacent strips 120 and to create a sufficiently
flexible connection between the plate 1 and the object O to be
deformed and absorb the deformations, in an amplified manner in
relation to the deformations applied to the object and the plate.
In other words, the strips 120 are deformed more rapidly and with
greater amplitude than the object O and the plate 1. In this way,
they absorb most of the deformations, making it possible to
optimise the retention of the nominal dimensional characteristics
of the object O and the plate 1.
[0040] Such a flexible connection between the object O and the
plate 1, due to the dimensions of each end 13, 14 of the strips
120, is sufficiently fragile to enable, when the object O is
finished, easy separation between the strips 120, the object O and
the plate 1 by means of techniques known per se, for example by
shearing with a sharp tool. In other words, the strips 120 are easy
to destroy when the object is produced and it is sought to separate
same from the plate, while limiting any further machining of the
object O.
[0041] FIG. 5 illustrates a first type of deformation with the
concavities 21, 91 of the surfaces 2, 9 illustrated with upward
phantom lines, when the strips 120 have absorbed the deformation.
In this case, the strips 120, at least those close to the periphery
of the absorbing member 12 are inclined towards the object O. As
shown in FIG. 5, this inclination is variable; it is generally
greater at the periphery, in the vicinity of the sides of the
object O, than at the centre of the absorbing member 12. The strips
120 situated in the central position remain substantially
perpendicular to the surface 2 of the plate 1 during the absorption
of the deformation.
[0042] FIGS. 7 and 8 illustrate a second type of deformation with
the concavities 20, 90 of the surfaces 2, 9 oriented in the other
direction in relation to FIGS. 5, 6, i.e. situated towards the
bottom wall with reference to FIG. 7. As above, the concavities 20,
90 are represented with phantom lines. The strips 120 then tend to
be oriented towards the outside of the absorbing member 12. The
most inclined strips 120 are situated at the periphery, in the
vicinity of the sides of the object O. The strips situated in the
central position also remain, during the absorption of the
deformation, substantially perpendicular to the surface 2 of the
plate 1.
[0043] Such an absorbing member may also be positioned between at
least two areas of at least one object, i.e. a step for
manufacturing a deformable substrate may be included, not only as
described, between the plate 1 and an object O, but between two
areas of an object O or between two objects liable to be deformed
for example, because they do not have the same thermal expansion
coefficients and/or because they are made of two different
materials. In this case, one surface of the object acts as the work
area receiving the powder to be compacted and sintered.
* * * * *